cummings



c. L.. cUMMlNGs 2,733,615

mxo CHANGER 3 Sheets-Sheet 1 @u1u a+ 7 2 Hmm m s 4 @m v2 d wmp. 3 0

Feb. 7, 1956 Filed Aug. 22, 1951 Feb. 7, 1956 c. l.. cuMMlNGs 2,733,615

RATIO CHANGER Feb. 7, 1956 c. L. cUMMlNGs A 2,733,615

RATIO CHANGER Filed Aug. 22, 1951 3 Sheets-Sheet 5 5 Iaweazud;

waaien/L. cumming;

United States .Patent" F This invention relates tcl rali() changers particularly Well suited for Use'Wl'len .spatie and Weight factors are Critical lir'n'itatiol's'. v l

While the invention s adapted for many other uses,

its novelf'eatures' and advantages may be most readily understood by reference to vrecorders where it is usually desirable to provide means to vary the speedof 4tl1 e tap'e relative-to Ithe recording instrument. The conventional `ratio changers employed for rsuch purposes require the removal of nuts o`r` screws to enable 'the change of ratios to be effected; This makes ratio changing difficult and time consuming since the use of both hands is required. vIn accordance wwith the invention, first and second iiitl'e'rehncted Coaxial gears of different diameters are ported for movement along an arcuate pathway concentric with a r'st gear With which the ilst of the coaxial gears meshes. This enables the first coaxial Vgear toi remain in mesh with 'the rst gear `as the second coaxial gear is moved, as required by its diameter, towardsor away from the gear with which it is to mesh.` vOf the two coaxial gears, at least the second is adapted to be quickly and easily kremoved and replaced. Because of the pathwayalongwhich the coaxial gears may move, a

saar .train --mar prende.. .a suitable', range 0f gear. tati@ changes as it is possible to employ any one of a set of gears of different diameters as an intermediate gear.

Ratio changes in accordance with the invention meet such general requirements as compactness, lightness in.

weight and simplicity of construction. Ease and accuracy in establishing different ratios are assured since only a single gear or single gear unit needs to be removed and replaced to effect a ratio change and such may be done with one hand simply and quickly.

In the accompanying drawings, an embodiment of the invention is shown that illustrates these and other of its novel features and advantages.`

In the drawings:

Fig. l1 is a view, in elevation, of a ratio changer employing a replaceable intermediate gear of one diameter,

Figs. 2, 3 and 4 are sections taken along the indicated lines 2 2, 3 3, and 4 4, respectively, of Fig. l,

Fig. 5 is a view, similar to Fig. 1, but with an intermediate gear of a diierent diameter, and

Fig. 6 is an exploded view of the housing showing the details of its construction and certain of the gear supporting means.

The ratio changer shown in the drawings is adapted for use in a recorder to enable the speed of the tape to be varied. The recorder is not shown but it will be appreciated that a ratio changer therefor must be compact and light from the fact that the changer is drawn to approximately twice its actual size. A typical recorder includes a driven shaft 10 in the form of a sleeve through which extends the drive shaft 11.

The ratio changer includes a housing consisting of a base plate 12 provided with a spacer 13 through both of which extend holes to enable the housing to be attached 733,6 l 5 Patented Ffeb. 7, *1956- ICC to the recorder or other apparatus Yby screws. The 'shafts 10 and 11 'xtd through' the plate 12 and 'carry gears 14 and 1s,ieipecc ive1yl The base plate 12 is bored to receive a pair of flanged spindles' 16; one or these rotatably supports a gear 17 which lheshes with ali idler gear rotatably mo'uflted on the 'other spindle 16. The idler 18 with the drivenfsliart .gear 1a.

arnrla is' `sy'viiigably supported by the shaft 10 and isY located 'between-'the gear 14 and the base plate 12. The arm 19 is provided with a pin 20 to slidably receive and 'rotatably support a pair'of gears of which the gear 21 is fo' mesh with the drive shaft gear 115 and the gear lzz is to mesh with gear 17.I This .pair ot gea-rs is coaxial and preferably interconnected as u'nit and because they are mounted on thearm 19,1theymay'be moved 4along an arcuate pathway concentric with the shaft axis. The gear 21, accordingly, "remains in mesh with the gear 15 as ther arm l9 is swung-to carry the gear 'z2 towards or away from the gear'17 to enable 'them to intermesh: The gear `22 may be replaced, therefore, by a gear of adiiererit diameter such as the 'gear 23 n is necessary 'to 'proyidem'eans 'to' lock the" ainin against movement when it` has been properly positioned. Such means may conveniently consist o'f a clamping riii 24 recessed as'at z5 to' receive the" free end ci the arm 19. The housing a cover 26 including a side wall 27 and Jspacers 28 and 29. The cover 26 is a'ttache-d to the base plate 1a By screws so, 31, and l32 withthe screw 32 extending through the spacer 28 and one end croie clamping arm 124-. The spacer 29 func tions to'h'old the gears 17and 18 on their spindles;

A screw '3s-extends through the center 'part of the 'clamp-fag arm 24 and is threaded imo the base 'plate 12 Vso that by trniiigit iii one direction oi' the other, the

tion in` which the swigble sidi 1a` is locked against vino-'veide-:nc e4 and: uns is disposedwhen-theatreunlocked eter to vary the ratio between the drive and driven elements that it connects. With a set of such intermediate gears, a suitable range of gear ratio changes is provided.

What I therefore claim and desire to secure by Letters Patent is:

1. In a ratio changer comprising a gear train including first and second gears, one of which is a driving gear, an arm swingable about the axis of said rst gear towards and away from said second gear and including a stud, first and second interconnected coaxial gears of different diameters slidably and rotatably supported by said stud with said first coaxial gear in mesh with said rst gear as said arm is swung to enable said second' coaxialgear to be positioned in mesh with said second gear, thereby to enable ratio changes to be eiected by substituting for said `coaxial gear a gear of different diameter, and means to lock said arm against movement when it has been positioned to mesh said second coaxial gear with said second gear, said means including a handle positioned to retain said coaxial gears on said stud when said locking means is operative.

2. A ratio changer to interconnect coaxial driving said shafts extend, an arm swingably mounted on the outer shaft, means carried by said support overlying theV free end of said arm and operable to clamp it against said support, a` gearftrainto interconnect said shafts, saidgear train including a gear fast on each of4 said shafts, at least one gearrotatably mounted on said support, and a gear unit, said unit comprising first and/second coaxial, interconnected gears of different, diameters, said arm including a stud receiving and rotatably supporting said unit with said first gear meshing with one of said shaft gears as said arm is swung towards and Vaway from said support the distance, yrequired by the; diameter of said second gear, to ,effect its -meshing Vwith said support mounted gear. 1 l .,t 1'

3. A ratio changer to interconnect coaxial driving and driven shafts and comprising a support through which saidshafts extend, an arm swingably mounted o n the outer`shaft, means carried by said support overlying the free end ofk said arm `and operable Vto clamp it against s aid,support and including an operating screw, a gear train to interconnect said shafts, said gear train including a gear fast Yon each of said shafts, at least one gear rotatably mounted on saidsupport, and a gear unit, said unit comprising first and second coaxial, interconnected gears vof differentjdiameters, said arm including astud slidably receiving and rotatably supporting said unit with said lirstgear meshing with one of said shaft gears as said arm is swung towards and away from said support the distance, required bythe diameter of said second gear, to effect itsmeshing with Asaid support mounted gear, said operating screwincluding a handle disposed to function as a retainer for said unit when said screw has been turned to elect the operative position of said clamping means.

4. In a ratio changetgpdrive and driven shafts one extending through the other, a gear train interconnecting Vsaid shafts to establishl apredetermined ratio therebebetween, said gear train including drive and driven shaft gears, an intermediate unit comprising irst and second interconnected coaxial gears of different diameters of which the first meshes with one shaft gear, and a -third `gear with which the other shaft gear meshes, means to rotatably supportsaid coaxial gears for movement along an arcuate pathway concentric with'said shafts towards and away from said third gear thus to enable the gear VVratio of the train 'to be varied by substituting for said second coaxial gear a gear of different diameter.

5. In a ratio changer, drive and driven shafts one extending through the other, a gear train interconnecting said shafts to establish a predetermined ratio therebetween, said gear train including drive and driven shaft gears, an intermediate unit comprising first and second interconnected coaxial gears of different diameters of which the first meshes with one shaft gear, and a third gear with which the other shaft gear meshes, an arm, a stud and socket connection between said arm and said unit enabling said unit to be slipped into andout of place therein, said arm being movable along an arcuate pathway concentric with said shafts, thus to enable the gear ratio of the train to be varied by substituting for said second coaxial gear a gear of different diameter, and a keeper pivotally mounted to swing into-v and out of a position in which it holds said unit on said arm.

6. In a ratio changer, drive and driven shafts one extending through the other, a gear train interconnecting said shafts to establish a predetermined ratio therebetween, said geartrain including drive and driven shaft gears, an intermediate u nit comprising first and second interconnected coaxial gears of different diameters of which the first meshes with one Ashaft gear, and a third gear with which the other shaft `gear meshes, an arm, a studand socket connection between said arm and said unit enabling said unit to be slipped into and out of place therein, said arm being swingable to move said connection along an arcuate pathway concentric with said shafts, thus to enable the gear ratio of the train to be varied by Ysubstitutingfor said second coaxial gear a gear of different diameter, means to clamp said arm against movement and including a manually adjustable element engageable with said unit when said arm is clampedA to hold said unit on saidarm.

VReferences Cited in the kiile of this pate'nt UNITED STATES PATENTS Schneider V. Nov. 20, 1934 

